﻿using System;

namespace Program11
{
    class Program
    {
        static void Main(string[] args)
        {
            int n;
            int f=1;
            Console.WriteLine("请输入n的值");
            n = Convert.ToInt32(Console.ReadLine());
            if (n == 0||n==1)
            {
                return ;
            }
            else
            {
                for(int i = 1; i <= n; i++)
                {
                    f *= i;
                }
                Console.WriteLine("值为{0}", f);
            }
        }

        
    }
}
